Reading in a line of text and breaking it up, complicated

Question

Hi all,
At the moment im reading in a few 100 lines of text from a file, each line contains a command and a few variables which need to be set to existing variables I have created shown below;
Int variableA ;
Int variable B ;
Int variable C;
Int Variable D;
However I have no way to know which command will go with which variables,
On every line there will be one command and two variables..
The possible command are; ADD, SUB, TIMES, Divide, COPY, SET
And the text coming in look like this;
SET A10, B15 // set each variable
SET C33, D50 // as above
COPY A, B // which means assign copy what ever in variableA to variableB
ADD C, D // which mean add variableC�s contents to variableD contents
SUB B, C // which is subtract variableC contents by what ever is in variableB
Does anybody know of a way where I can test what the next command is, and assign the correspond variables , so far I have come up with;
But am not sure if this is the best way to go about it, was thinking maybe I should put the text file into an array, which might make it easyer to process.
public static void main (String [] args)
int D = 0 ;
int C = 0 ;
int B = 0 ;
int A = 0 ;
StringTokenizer st ;
String line ;
String buffer = "";
String file ="test2.txt" ;
String name = "";
String billy = "";
try
FileReader fr = new FileReader(file) ;
BufferedReader inFile = new BufferedReader (fr) ;
//read in one line @ a time
buffer =inFile.readLine() ;
while (buffer !=null)
StringTokenizer words = new StringTokenizer (buffer) ;
//put the buffer "line" into a tokenizer for individual characters out of a line;
while(words.hasMoreTokens())
String letter = words.nextToken() ;
if(letter.charAt (0) == 'S') // if first letter = S would be SET
System.out.println(letter) ;
//display the token as a test output;
if(letter.charAt (0) == 'A') // if letter = A would be ADD
System.out.println(letter) ;
buffer = inFile.readLine() ;
     //read in next line
inFile.close();
catch (FileNotFoundException e)
System.out.println("File not found");
catch ( IOException e)
System.out.println("IO Exception") ;
}

Answer 1

hi,
i think that what u r tring to do is "parsing" where u translate these primatin=ve commands to execute them, if so here what u need to do:
Rad a line untell end of file
for each token in the line
if(token="SET" || token="ADD || token=""SUB")
{       //save operation for later use
operation=token;
//now u expect the next token to be an operand
token=nextToken;
if (token!="" and token!=",")//it must be an operand
{operand1=token;
token=next token;
if(token=",")//do nothing just read the nest operand
token=nexttoken;
else //syntax error in file, exit ;
if (token!="" and token!=",")//checking the 2nd operand
operand2=token;
//now check value of operation and call the right method and send operand1,operand2 as arguments to get the result e.g
if(opration=="ADD")
system.println("result of addition is"+addMethod(operand1,operand2));
hope that helps,
Insighter